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Feb 19, 2026 8:01 AM

Merck Discloses Positive Data For Respiratory Syncytial Virus Antibody Treatment, Seeks FDA Nod For Broader Child Use

Merck & Co. (NYSE:MRK) on Thursday shared positive second RSV season findings from the Phase 3 SMART trial.

The results from the SMART trial were presented at the RSVVW Conference and will be shared with the U.S. Food and Drug Administration (FDA) for evaluation for an expanded indication in children at increased risk for severe Respiratory Syncytial Virus (RSV) disease.

New data from the SMART trial in children under 2 years of age showed that safety was generally consistent with safety observed in MK-1654-007 infants who received Enflonsia during the RSV season.

Enflonsia (clesrovimab), the monoclonal antibody being evaluated, is currently approved for use in infants during their first RSV season and aims to provide protection through five months.

In the trial, safety data showed consistency with previous findings, and the monoclonal antibody serum concentrations achieved were similar to those in